JP2004225642A - Cooling fan for electric tool, and electric tool equipped with cooling fan - Google Patents

Cooling fan for electric tool, and electric tool equipped with cooling fan Download PDF

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Publication number
JP2004225642A
JP2004225642A JP2003015799A JP2003015799A JP2004225642A JP 2004225642 A JP2004225642 A JP 2004225642A JP 2003015799 A JP2003015799 A JP 2003015799A JP 2003015799 A JP2003015799 A JP 2003015799A JP 2004225642 A JP2004225642 A JP 2004225642A
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Japan
Prior art keywords
main plate
blade
output shaft
hub
cooling fan
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Pending
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JP2003015799A
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Japanese (ja)
Inventor
Tomomasa Nishikawa
智雅 西河
Shinki Otsu
新喜 大津
Takuma Nonaka
琢磨 野中
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Koki Holdings Co Ltd
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Hitachi Koki Co Ltd
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Priority to JP2003015799A priority Critical patent/JP2004225642A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling fan for an electric tool and an electric tool equipped with a cooling fan, in which a shape of reinforcement ribs is optimized and a flow velocity generated by the reinforcement ribs is set to be slower than a flow velocity generated by blades, so that occurrence of noise is suppressed while ensuring strength of hubs and a main plate. <P>SOLUTION: The cooling fan 20 comprises: the main plate 22 in a shape of a disc; a fan main body 2 having the hubs 23 disposed integrally with a base portion of the main plate to extend in a rotation shaft center direction; the blades 25 project from one face side of the main plate and circumferentially arranged with predetermined pitches; and ribs 26 projecting from the other face side of the main plate and extending outward in a radial direction from the hubs to reinforce the blades and the main plate. The main plate is in a shape inclined with respect to a shaft center so that an outer edge of the main plate is positioned to be closer to a side opposite to the blades than the base portion. A projecting end of each rib becomes closer to a blade side as the projecting end becomes closer to the outside in the radial direction of the rib, and length in the radial direction of the ribs is reduced to suppress increase in velocity of air flow generated by the ribs and flowing toward the outside in the radial direction. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は電動工具用冷却ファン、特にファン本体の半径方向外方に冷却空気を排出する遠心ファンに関する。本発明は更に、かかる遠心ファンを備える電動工具に関する。
【０００２】
【従来の技術】
従来の冷却ファンを備えた電動工具の一例としての研削工具について、図８に基づき説明する。研削工具１０１は、ケーシング１０２内に出力軸１０４を備えるモータ１０５が支持され、また出力軸１０４に接続される冷却ファン１２０が設けられる。ケーシング１０２の他端部にはギヤカバー１０３が固定され、ギヤカバー１０３内にはピニオンギヤ１０８とギヤ１１０を含む動力伝達機構が配置され、出力軸１０４の回転を駆動軸１０９に伝達している。そして駆動軸１０９には研削部材１１３が固定されている。ケーシング１０２の一端側と、中間部には空気吸入口１０２ａ、１０２ｂが形成され、ギヤカバー１０３には空気吐出口１０３ａが形成されている。冷却ファン１２０はモータ１０５に対し空気吸入口１０２ａとは反対側に位置する。
【０００３】
冷却ファン１２０は、モータ１０５の出力軸１０４に固定されるディスク状のファン本体１２１と、空気をファン本体１２１の半径方向外方に排出するために、ファン本体のモータと対向している一面側に設けられた複数の羽根１２５とを有する。羽根１２５は、周方向に沿って所定ピッチで配列されて略半径方向に延び、一面側から出力軸１０４の軸方向に突出している。そして吐出口１０３ａは冷却ファン１２０の外周縁近傍に位置する。また冷却ファン１２０近傍のベアリングの保持のために、２本のネジ１１５が冷却ファン１２０の他面側に向かって突出しており、且つ他面側に直面している。
【０００４】
モータの出力軸１０４が回転すると、出力軸１０４に固定されたピニオン１０８と駆動軸１０９に固定されたギヤ１１０の噛合により駆動軸１０９に回転が伝達され，駆動軸１０９に取付けられた研削部材１１３の回転により研削作業が実行できる。モータ１０５の回転に伴い冷却ファン１２０が回転して吸気口１０２ａ、１０２ｂより矢印のようにケーシング１０２とモータ１０５との間のスペース内に冷却風が導入される。そして、冷却ファン１２０の内径部より半径方向外方に冷却風が流出し、吐出口１０３ａより外部に排出される。
【０００５】
ここで電動工具の小型化、高出力化、低騒音化の要求から、小型で冷却能力が高く、騒音の小さいモータ冷却ファン及びファン周辺の開発の必要性が高まっている。そこで風量増加と騒音低減を目的として、羽根の形状の最適化が提案されている。（例えば特許文献１参照）。
【０００６】
【特許文献１】
特開平１０−１５３１９４号公報
【０００７】
図９に示されるように、特許文献１記載の冷却ファンの複数の羽根１２５は、空気をファン本体１２１の主板１２２の半径方向外方に排出するために、主板１２１の一面側において主板の所定半径位置から主板の外縁まで延び、主板の周方向に沿って所定ピッチで配列され、一面側から出力軸の軸方向に突出して設けられている。
【０００８】
冷却ファン１２０を回転させると、遠心作用により空気にエネルギが与えられ，空気は、羽根１２５の内端である入口部より主板１２２，羽根１２５およびファンガイド１３１により形成された風路を通過して羽根１２５の外周部である出口部より半径方向外方に排出される。
【０００９】
ここで冷却ファン１２０は、羽根を主板の所定半径位置から半径方向外方に延びる方向に対し回転方向と逆方向の傾斜を設けている。これはファン回転時の騒音は一般に流速に寄与するものが多く、流体騒音は流速の６乗に比例すると言われていることから、ファン回転時にファン内部の羽根間を通過する流速をファンの回転周速度よりもを遅くすることで低騒音化を図るためである。また、羽根１２５の主板１２２からの突出長は、ファン回転時において羽根１２５の内径側頂点１２５ａから外周側まで流速が等しくなるかもしくは徐々に遅くなるように設定されている。具体的には、各羽根１２５間の主板周方向の間隔と羽根１２５の突出長の積からなる面積と、直径との積が各半径位置においてほぼ等しくすることにより騒音を低減している。即ち、図９に示されるように、冷却ファンの羽根の任意の直径Ｄにおける各羽根間の間隔および各羽根の突出長さを夫々Ｌおよびｈとしたとき、Ｌ×ｈ×Ｄが一定となるようにして、円滑に冷却風が流れて騒音低減の効果が発揮される。
【００１０】
ここで図９に示されるように、主板１２２を回転軸心Ｃに対して直角に設けると、主板１２２と羽根１２５に作用する遠心力により、主板１２２の反りが発生し、主板１２２が変形湾曲するという問題がある。特に研削作業の高速化を目的として、モータの回転を高速化した場合にこの問題が顕著となる。
【００１１】
この問題を解決するために、図１０に示されるように、羽根を設置している主板２２２を回転軸心Ｃに対して垂直に設けずに、主板２２２の外周縁２２２Ｂが主板の基部２２２Ｃよりも反羽根側に位置するように主板２２２を傾斜させる構成が実施されている。この構成により、羽根１２５と主板２２２の合計重心を羽根付け根位置に近づけることができ、ファンの回転時における遠心力による主板２２２の反りや変形が抑えられる。
【００１２】
しかし遠心ファンの回転により、主板２２２に矢印Ｘ方向の力が作用すると、出力軸と嵌合するハブ２２３と主板の基部２２２Ｃの接続部において引張り力が作用して、主板２２２が破損する可能性がある。そこで、図１１に示されるように、出力軸に嵌合するハブ３２３を羽根側方向のみならず、反羽根側方向にも出力軸の軸方向に延設し、主板２２２の他面側において、ハブ３２３から主板の軸心Ｃと直交する面２２２Ｄを備えた部分まで軸心Ｃと直角に主板２２２の半径方向に延びる複数の補強リブ３２６を一体に設ける構成が実施されている。
【００１３】
【発明が解決しようとする課題】
しかし、半径方向に延びる複数の補強リブ３２６を設けたために、羽根１２５と同様に補強リブ３２６によっても遠心作用により空気流を発生させてしまう。補強リブ３２６については、上述した羽根に関する騒音低減のための構成はなく、羽根１２５間を通過する流速よりも速くなる可能性が高い。そのため補強リブ３２６が発生させる流速が騒音を増加させる要因となる。特に電動工具の空気吐出口が、羽根側ではなく補強リブ側に偏して位置している場合には、音源が即座に外部に通じるので、騒音の問題が顕在化する。
【００１４】
また図８の構成において、図１１と同様な構成の遠心ファンを採用すると、補強リブ３２６が周期的に突出物、即ちファン側に突出した複数のネジ１１５を通過する。その際の空気の圧力変動により騒音が発生するが、このとき２個の補強リブが２個のネジ１２５を同時に通過する事態となると、騒音が倍増する結果となる。
【００１５】
そこで本発明は、補強リブの形状を最適化し、補強リブが発生させる流速が羽根が発生させる流速よりも遅く設定することで、ハブおよび主板の強度を確保しつつ騒音の発生を抑制する電動工具用冷却ファン、及び該冷却ファンを備えた電動工具を提供することを目的とする。
【００１６】
【課題を解決するための手段】
かかる目的を達成するため、本発明は、円板状の主板と、該主板の半径方向内端側に一体且つ同軸に設けられて該主板の基部をなす筒状のハブとが設けられ、該ハブによりモータの出力軸に固定されるファン本体と、空気を該主板の半径方向外方に排出するために、該主板の一面側において該主板の第１所定半径位置から該主板の外縁まで延び、該主板の周方向に沿って配列され、該一面側から該出力軸の軸方向に突出して設けられた複数の羽根を備え、該主板は、該外縁が該基部よりも反羽根側方向に位置するように該出力軸の軸心に対して傾斜して設けられ、該ハブは羽根側方向と反羽根側方向に該出力軸の軸方向に延び、該主板の他面側には該ハブから該主板の第２所定半径位置まで該主板の半径方向に延びる複数の補強リブが一体に設けられる電動工具用冷却ファンにおいて、
該補強リブの、該主板の他面側及び該ハブと一体化する辺以外の外縁は、該羽根側に近づく形状をなす電動工具用冷却ファンを提供している。
【００１７】
ここで、該羽根は該一面からの突出長が、該羽根の半径方向内端から第３所定半径位置までは増加して第３所定半径位置でピークをなし、該第３所定半径位置から該羽根の半径方向外端に向かって徐々に減少する形状をなし、該複数の補強リブの半径方向外端をなす該第２所定半径位置は、該第３所定半径位置と該羽根の半径方向内端との間に位置する。
【００１８】
本発明は更に、円板状の主板と、該主板の半径方向内端側に一体且つ同軸に設けられて該主板の基部をなす筒状のハブとが設けられ、該ハブによりモータの出力軸に固定されるファン本体と、空気を該主板の半径方向外方に排出するために該主板の一面側において該主板の第１所定半径位置から該主板の外縁まで延び、該主板の周方向に沿って配列され、該一面側から該出力軸の軸方向に突出して設けられた複数の羽根を備え、該主板は、該外縁が該基部よりも反羽根側方向に位置するように該出力軸の軸に対して傾斜して設けられ、該ハブは羽根側方向と反羽根側方向に該出力軸の軸方向に延び、該主板の他面側には該ハブから該主板の第２所定半径位置まで該主板の半径方向に延びる複数の補強リブが一体に設けられる電動工具用冷却ファンにおいて、該補強リブの、該主板の他面側及び該ハブと一体化する辺以外の外縁は、該羽根側に近づく形状をなし、該複数の補強リブの半径方向外端位置となる該第２所定半径位置は、該ファン本体の回転により該複数の補強リブが発生する半径方向外方に向かう空気の流速が、該複数の羽根が発生する半径方向外方に向かう空気の流速以下となるように設定される電動工具用冷却ファンを提供している。
【００１９】
本発明は更に、空気吸入口と空気吐出口が形成された外枠体と、該外枠体内に支持され出力軸を備えるモータと、該外枠体内に配置されると共に該出力軸に接続される冷却ファンとを備え、該冷却ファンは、円板状の主板と、該主板の半径方向内端側に一体且つ同軸に設けられて該主板の基部をなす筒状のハブとが設けられ、該ハブによりモータの出力軸に固定されるファン本体と、空気を該主板の半径方向外方に排出するために該主板の一面側において該主板の第１所定半径位置から該主板の外縁まで延び、該主板の周方向に沿って配列され、該一面側から該出力軸の軸方向に突出して設けられた複数の羽根を備え、該主板は、該外縁が該基部よりも反羽根側方向に位置するように該出力軸の軸心に対して傾斜して設けられ、該ハブは羽根側方向と反羽根側方向に該出力軸の軸方向に延び、該主板の他面側には該ハブから該主板の第２所定半径位置まで該主板の半径方向に延びる複数の補強リブが一体に設けられ、該空気吐出口は、該主板に関して該他面側に偏して位置する電動工具において、該補強リブの、該主板の他面側及び該ハブと一体化する辺以外の外縁は、該羽根側に近づく形状をなす電動工具を提供している。
【００２０】
本発明は更に、空気吸入口と空気吐出口が形成された外枠体と、該外枠体内に支持され出力軸を備えるモータと、該外枠体内に配置されると共に該出力軸に接続される冷却ファンとを備え、該冷却ファンは、円板状の主板と、該主板の半径方向内端側に一体且つ同軸に設けられて該主板の基部をなす筒状のハブとが設けられ、該ハブによりモータの出力軸に固定されるファン本体と、空気を該主板の半径方向外方に排出するために該主板の一面側において該主板の第１所定半径位置から該主板の外縁まで延び、該主板の周方向に沿って配列され、該一面側から該出力軸の軸方向に突出して設けられた複数の羽根を備え、該主板は、該外縁が該基部よりも反羽根側方向に位置するように該出力軸の軸心に対して傾斜して設けられ、該ハブは羽根側方向と反羽根側方向に該出力軸の軸方向に延び、該主板の他面側には該ハブから該主板の第２所定半径位置まで該主板の半径方向に延びる複数の補強リブが一体に設けられ、該空気吐出口は、該主板に関して該他面側に偏して位置する電動工具において、該補強リブの、該主板の他面側及び該ハブと一体化する辺以外の外縁は、該羽根側に近づく形状をなし、該複数の補強リブの半径方向外端位置となる該第２所定半径位置は、該ファン本体の回転により該複数の補強リブが発生する半径方向外方に向かう空気の流速が、該複数の羽根が発生する半径方向外方に向かう空気の流速以下となるように設定される電動工具を提供している。
【００２１】
上述した電動工具において、該羽根は該一面からの突出長が、該羽根の半径方向内端から第３所定半径位置までは増加して第３所定半径位置でピークをなし、該第３所定半径位置から該羽根の半径方向外端に向かって徐々に減少する形状をなし、該複数の補強リブの半径方向外端なす該第２所定半径位置は、該第３所定半径位置と該羽根の半径方向内端との間に位置する。
【００２２】
また上述した電動工具において、該外枠体は、一端部側に該空気吸入口が形成されたケーシングと、該ケーシングの他端部に接続され該吐出口が形成されたギヤカバーとを有し、該ギヤカバーは該主板の他面に直接対向する位置に配置され、該ギヤカバーにより回転砥石を回転可能に支承して該電動工具は研削工具として機能し、複数のネジが一定の周方向間隔で該ケーシングの他端部に固定されると共に該主板の他面に向かって突出して該複数の補強リブに直接対向して配列され、
該複数の補強リブは一定の周方向間隔で配列され、該補強リブが奇数個のときは該ネジは偶数個設けられ、該補強リブが偶数個のときは該ネジが奇数個設けられる。
【００２３】
又は、上述した電動工具において、該出力軸の自由回転を阻止するために、該外枠体には、該主板の他面に直接対向する位置に該主板の直径方向に横切りかつ該直径方向に移動可能で該出力軸と選択的に嵌合する長尺状のスピンドルロックが設けられ、該スピンドルロックに関し該冷却ファンと反対側には丸鋸が着脱可能に設けられて該電動工具を切断工具として機能させ、該複数の補強リブは一定の周方向間隔で奇数個設けられる。
【００２４】
【発明実施の形態】
本発明の第１の実施の形態による電動工具について図１乃至図６に基づき説明する。第１の実施の形態は切断工具に関する。
【００２５】
切断工具１は、本体ハウジング２とギヤカバー３とにより外枠体が構成され、本体ハウジング２の一端には空気吸入口２ａが形成され、本体ハウジング２内には出力軸４を備えるモータ５が支持される。モータ５の後方と本体ハウジング２の間には、空気吸入口２ａに連通する空気通路ａ１が画成され、またモータ５の外周と本体ハウジング２の内周面との間は、空気通路ａ１に連通するモータ軸方向に沿った空気通路ａ２が画成される。そして出力軸４には冷却ファン２０が同軸に設けられる。また、モータ５と冷却ファン２０との間には、空気通路ａ２に連通し、冷却ファン２０の半径方向外方に向かう空気通路ａ３が画成される。
【００２６】
ギヤカバー３はその一端側が本体ハウジング２の他端部にねじ６により固定され、他端側には丸鋸ケース７が一体に設けられる。ギヤカバー３内には、軸受１１を介して出力軸４が回転可能に支承され、また軸受１２を介して駆動軸９が回転可能に支承される。出力軸４にはピニオンギヤ７が固定され、駆動軸９にはピニオンギヤ７と噛合するギヤ１０が同軸に固定されている。そしてこれらピニオンギヤ７やギヤ１０が動力伝達機構を構成してギヤカバー３内に配置される。またギヤカバー３内には本体ハウジング２内の空気通路ａ３と連通する吐出口３ａが形成され、吐出口３ａ内は、空気通路ａ４が画成される。駆動軸９には丸鋸刃１３が着脱可能に固定されると共に、セフティカバー１４が駆動軸９に回動可能に支持される。そして丸鋸刃１３と丸鋸ケース７との間の空間は、空気通路ａ４と連通し、外部に通じる空気通路ａ５が画成される。
【００２７】
図２に示されるように、本体ハウジング２とギヤカバー３との境界には一部隙間が形成されており、この隙間内に出力軸４の自由回転を阻止するためのスピンドルロック１５が設置されている。スピンドルロック１５は、切断工具１の非作動時に駆動軸９の自由回転を阻止して丸鋸刃１３の交換を容易にするために設けられる。
【００２８】
スピンドルロック１５は、冷却ファン２０の直径方向に横切りかつ図２の矢印Ａに示されるように直径方向に移動可能に設けられる長尺板状の部材である。スピンドルロック１５の一端は、外枠体の外部に突出し外部から操作可能とされる。図３に示されるように、出力軸４は、互いに平行な面を備えた異形断面部４Ａを備え、異形断面部４Ａと係合して出力軸４の回転を阻止する二股部１５Ａと、二股部１５Ａに連通し異形断面部４Ａと非係合関係にある回転許容部１５Ｂと、他互いに反対方向に延びる腕部１５Ｘ、１５Ｙを有する。よってスピンドルロック１５が矢印Ａ方向に移動操作されると、二股部１５Ａが異形断面部４Ａと係合して出力軸４の自由回転を阻止し、もって駆動軸９の自由回転が阻止され、反矢印Ａ方向に移動操作されると、回転許容部１５Ｂが異形断面部４Ａの周囲に位置して出力軸４の回転が許容される。
【００２９】
図２に示されるように、冷却ファン２０は、ファン本体２１と、複数の羽根２５と、複数の補強リブ２６とを備えた一体成形品である。ファン本体２１に関し羽根２５は、モータ５に面する側に設けられ、補強リブ２６はスピンドルロック１５に直面する側に設けられる。また上述した吐出口３ａは、補強リブ２６側に偏した位置にある。
【００３０】
図４乃至図６に示されるように、ファン本体２１は、円板状の主板２２と、主板２２の半径方向内端側に一体且つ同軸に設けられて主板２２の基部をなす筒状のハブ２３とを有し、ハブ２３がモータ５の出力軸４に圧入されることにより、冷却ファン２０が出力軸４に固定される。複数の羽根２５は、主板２２の一面側（モータ５に対向する側）において主板２２の第１所定半径位置２２Ａから主板２２の外縁２２Ｂまで延び、主板２２の周方向に沿って所定ピッチで配列される。そして一面側からモータ５方向に突出して設けられる。ここで主板２２は、外縁２２Ｂが基部２２Ｃよりも反羽根２５側方向に位置するように出力軸４の軸心Ｃに対して傾斜して設けられ、ハブ２３は羽根側方向と反羽根側方向に出力軸４の軸方向に延設されている。
【００３１】
冷却ファン２０回転時に羽根２５間を通過する空気の流速を冷却ファン２０自体の回転周速度よりもを遅くすることで低騒音化を図るために、図４に示されるように、それぞれの羽根２５は、主板２２の第１所定半径位置２２Ａから半径方向外方に延びる方向に対して回転方向Ｂと逆方向の傾斜をなしている。また、羽根２５の主板２２からの突出長は、ファン回転時において羽根２５の内径側頂点２５ａから外周縁２２Ｂまで流速が等しくなるかもしくは徐々に遅くなるように設計される。
【００３２】
形状的な言及をすれば、羽根２５は主板２２の一面からの突出長が、羽根の半径方向内端２２Ａから所定半径位置（第３所定半径位置）２２Ｄまでは急激に増加して第３所定半径位置でピーク２５ａをなし、第３所定半径位置２２Ｄから羽根の半径方向外縁２２Ｂに向かって徐々に突出長が減少する形状をなす。かかる構成により、各羽根２５間の主板周方向の間隔Ｌと羽根の突出長の積からなる面積と、半径との積が各半径位置においてほぼ等しくなり、もって騒音を低減することができる。
【００３３】
複数の補強リブ２６は、主板２２の他面側（スピンドルロック１５に直面する側）において、主板２２と一体にハブ２３から主板２２の所定半径位置（第２所定半径位置）２２Ｅまで主板２２の半径方向に延び、かつ周方向に一定間隔毎に奇数個設けられる。ここで、補強リブ２６は、突出端（請求項における外縁）が直線状をなすと共に、半径方向外方に向かうに従って羽根２５側に近づく形状をなす。
【００３４】
複数の補強リブ２６の半径方向外端（２２Ｅの位置に対応）は、羽根２５のピーク２５ａに対応する第３所定半径位置２２Ｄと羽根２５の半径方向内端２２Ａとの間に位置する。これは、遠心ファン２０においては、羽根２５間の流速が第３所定半径位置２２Ｄ近傍で最も速くなること及び、主板２２の強度を保つには補強リブ２３の半径方向外端径（２２Ｅ）が羽根の半径方向内端径以上必要であるからである。
【００３５】
以上の構成において、モータ５が回転すると、出力軸４、ピニオンギヤ８、ギヤ１０、駆動軸９を介して丸鋸刃１３が回転し、切断作業が実行できる。モータ５の回転により、空気吸入口２ａから本体ハウジング２内に空気が導入され、空気通路ａ１、ａ２を通じて空気が冷却ファン２０の羽根２５の内端側に導入され、空気通路ａ３のように空気が羽根の外端側に強制導入され吐出口３ａから空気通路ａ４、ａ５を経て外気に排出される。空気がモータ５の外周側の通路ａ２や丸鋸刃１３の外周縁側通路ａ５を通過することで、加熱要素であるモータ５が冷却される。
【００３６】
吐出口３ａは音源である補強リブ２６側に偏しているので、騒音を外方に伝達しやすいレイアウトとなるが、上述したように、補強リブ２６の外縁は、半径方向外方に向かうに従って羽根２５側に近づく形状をなしているので、補強リブ本来の機能であるハブ２３及び主板２２の機械的強度を確保することができると共に、同時に、補強リブ２６の半径方向の長さを小さくすることができるので、補強リブ２６が発生する空気流の速度を低下でき、補強リブ２６の回転による騒音の発生を抑えることが可能となる。
【００３７】
また、上述したように、複数の補強リブ２６の半径方向外端（２２Ｅの位置に対応）は、羽根２５のピーク２５ａに対応する第３所定半径位置２２Ｄと羽根２５の半径方向内端２２Ａとの間に位置しているので、補強リブ２６が発生する空気流の流速が羽根２５が発生する空気流の流速よりも遅くなり、騒音を増加させることなく十分な強度を得ることが可能となる。
【００３８】
更に遠心ファン２０の１回転当たり、それぞれの補強リブ２６はスピンドルロック１５を２度通過することになる。即ちスピンドルロックの腕部１５Ｘと腕部１５Ｙを通過する。補強リブ２６がスピンドルロック１５を通過するときにも、空気の急激な圧力変動により騒音が発生することは避けられない。この騒音は騒音値としては小さいものの、高周波を発生させるために耳障りな音となり不快感を与える。本実施の形態では、複数の補強リブ２６が主板２２の周方向に等間隔に配列されつつも、奇数個であるので、スピンドルロック１５上を同時に２個の補強リブ２６が通過するのを避けられる。よって、騒音の同時発生を防止することができる。
【００３９】
図７は、冷却ファンの変形例を示しており、図５と同様な部分は同一の番号を付し説明を省略する。図７の冷却ファン３０は、補強リブ３６の突出端の形状が直線状ではなく、膨らみの円弧形状をなす。かかる円弧形状であっても、上述した主板２２とハブ２３との補強効果と、騒音低減効果を発揮することができる。
【００４０】
また図８に示される研削工具において、冷却ファン１２０に代えて、図５乃至図７に示される冷却ファンを採用することで、騒音低減効果が達成できる。また、図８の構成に図５乃至図７に示される冷却ファンを採用すると、冷却ファン方向に突出する２本のねじ１１５をそれぞれの補強リブが通過して、その際の空気の圧力変動により騒音を発生することになる。そこで上述した実施の形態と同様に、補強リブの本数を奇数個として、２個の補強リブが同時に２個のボルト１１５を通過しないようにして、騒音の同時発生を防止することができる。
【００４１】
本発明による電動工具は上述した実施の形態に限定されず、特許請求の範囲に記載した範囲で種々の変形や改良が可能である。例えば、騒音の発生源である補強リブ方向に突出する突起物（例えば図８のねじ１１５）が一定の周方向間隔で多数設けられている場合に、その個数が奇数個であれば補強リブを偶数個とし、突起物が偶数個であれば補強リブを奇数個とすればよい。また補強リブの外縁は図５に示されるような連続的な直線状や図７に示される円弧状のみならず、角部を有する不連続な線であってもよい。後者の場合に縁部を、ハブから軸心Ｃに対して垂直に立上がる第１縁部と第１縁部から直角に羽根側に向かう第２縁部により構成してもよい。また、上述した切断工具や研削工具以外の電動工具についても、上述した実施の形態による冷却ファンを採用することができるのは勿論である。
【００４２】
【発明の効果】
請求項１記載の電動工具用冷却ファンによれば、補強リブの、主板の他面側及びハブと一体化する辺以外の外縁は、羽根側に近づく形状をなしているので、補強リブ本来の機能であるハブ及び主板の機械的強度を確保することができると共に、同時に、補強リブの半径方向の長さを小さくすることができるので、補強リブが発生する空気流の速度を低下でき、補強リブの回転による騒音の発生を抑えることができる。
【００４３】
請求項２記載の電動工具用冷却ファン及び請求項６記載の電動工具によれば、それぞれの補強リブの半径方向外端は、第３所定半径位置と羽根の半径方向内端との間に位置する構成であるので、補強リブが発生する空気流の流速が羽根が発生する空気流の流速よりも遅くなり、騒音を増加させることなく十分な強度を得ることが可能となる。
【００４４】
請求項３記載の電動工具用冷却ファンによれば、補強リブの、主板の他面側及びハブと一体化する辺以外の外縁は、羽根側に近づく形状をなし、複数の補強リブの半径方向外端位置となる第２所定半径位置は、ファン本体の回転により複数の補強リブが発生する半径方向外方に向かう空気の流速が、複数の羽根が発生する半径方向外方に向かう空気の流速以下となるように設定されているので、補強リブの回転による騒音の発生を抑えることができる。
【００４５】
請求項４記載の電動工具によれば、吐出口が音源である補強リブ側に偏しており、騒音を外方に伝達しやすいレイアウトであるが、請求項１と同様に、補強リブの、主板の他面側及びハブと一体化する辺以外の外縁は、羽根側に近づく形状をなしているので、補強リブの半径方向の長さを小さくすることができ、補強リブが発生する空気流の速度を低下でき、補強リブの回転による騒音の発生を抑えることができる。
【００４６】
請求項５記載の電動工具によれば、請求項４と同様に吐出口が音源である補強リブ側に偏しており、騒音を外方に伝達しやすいレイアウトであるが、請求項３と同様に、補強リブの、主板の他面側及びハブと一体化する辺以外の外縁は、羽根側に近づく形状をなしており、複数の補強リブの半径方向外端位置となる第２所定半径位置は、ファン本体の回転により複数の補強リブが発生する半径方向外方に向かう空気の流速が、複数の羽根が発生する半径方向外方に向かう空気の流速以下となるように設定されているので、補強リブの回転による騒音の発生を抑えることができる。
【００４７】
請求項７記載の電動工具によれば、電動工具が研削工具である場合に、補強リブが奇数個のときは突出物であるネジは偶数個設けられ、補強リブが偶数個のときはネジが奇数個設けられるので、２個の補強リブが２個のネジ上を同時に通過する事態を防止でき、騒音の重複発生を防止できる。
【００４８】
請求項８記載の電動工具によれば、電動工具が切断工具である場合に、補強リブは奇数個設けられているので、２個の補強リブが同時にスピンドルロックを通過する事態が防止でき、騒音の重複発生を防止できる。
【図面の簡単な説明】
【図１】本発明による電動工具を切断工具に適用した実施の形態を示す縦断面図。
【図２】本発明の実施の形態による図１の切断工具の一部断面平面図。
【図３】本発明の実施の形態による図１の切断工具において、本体ハウジングを取り除き、図２の矢印ＩＩＩ方向から見た図。
【図４】本発明の実施の形態による冷却ファン示す部分正面図。
【図５】本発明の実施の形態による冷却ファンの部分断面図。
【図６】本発明の実施の形態による冷却ファンの裏面図。
【図７】図４乃至図６に示される冷却ファンの変形例を示す部分断面図。
【図８】従来の電動工具の一例である研削工具を示す断面図。
【図９】従来の冷却ファンを示す説明図。
【図１０】回転軸心に対してファン本体を傾けた従来の冷却ファンを示す部分断面図。
【図１１】図１０の冷却ファンに補強リブを設けた構成を示す部分断面図。
【符号の説明】
１：切断工具、 ２：本体ハウジング、 ３：ギヤカバー、 ４：出力軸、５：モータ、 １５：スピンドルロック、 ２０：冷却ファン、 ２１：ファン本体、 ２２：主板、 ２２Ａ：第１所定半径方向位置、 ２２Ｂ：外縁、 ２２Ｃ：基部、 ２２Ｄ：第３所定半径方向位置、 ２２Ｅ：第２所定半径方向位置、 ２３：ハブ、 ２５：羽根、 ２５ａ：内径側頂点、 ２６ ３６：補強リブ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cooling fan for a power tool, and more particularly to a centrifugal fan that discharges cooling air radially outward of a fan body. The invention further relates to a power tool provided with such a centrifugal fan.
[0002]
[Prior art]
A grinding tool as an example of a power tool having a conventional cooling fan will be described with reference to FIG. In the grinding tool 101, a motor 105 having an output shaft 104 is supported in a casing 102, and a cooling fan 120 connected to the output shaft 104 is provided. A gear cover 103 is fixed to the other end of the casing 102, and a power transmission mechanism including a pinion gear 108 and a gear 110 is disposed inside the gear cover 103, and transmits the rotation of the output shaft 104 to the drive shaft 109. A grinding member 113 is fixed to the drive shaft 109. Air inlets 102a and 102b are formed at one end and an intermediate portion of the casing 102, and an air outlet 103a is formed at the gear cover 103. The cooling fan 120 is located on the opposite side of the motor 105 from the air suction port 102a.
[0003]
The cooling fan 120 has a disk-shaped fan main body 121 fixed to the output shaft 104 of the motor 105, and a surface facing the motor of the fan main body for discharging air to the radial outside of the fan main body 121. And a plurality of blades 125 provided at the same time. The blades 125 are arranged at a predetermined pitch along the circumferential direction, extend substantially in the radial direction, and protrude from one surface side in the axial direction of the output shaft 104. The discharge port 103a is located near the outer peripheral edge of the cooling fan 120. Also, two screws 115 protrude toward the other surface of the cooling fan 120 and face the other surface for holding the bearing near the cooling fan 120.
[0004]
When the output shaft 104 of the motor rotates, the rotation is transmitted to the drive shaft 109 by the engagement of the pinion 108 fixed to the output shaft 104 and the gear 110 fixed to the drive shaft 109, and the grinding member 113 attached to the drive shaft 109 The grinding operation can be performed by the rotation of. With the rotation of the motor 105, the cooling fan 120 rotates, and cooling air is introduced into the space between the casing 102 and the motor 105 from the intake ports 102a and 102b as shown by arrows. Then, the cooling air flows radially outward from the inner diameter of the cooling fan 120 and is discharged to the outside through the discharge port 103a.
[0005]
Here, due to the demand for downsizing, high output, and low noise of the power tool, the necessity of developing a motor cooling fan having a small size, a high cooling capacity and a low noise, and a periphery of the fan has been increased. Therefore, optimization of the blade shape has been proposed for the purpose of increasing the air volume and reducing noise. (See, for example, Patent Document 1).
[0006]
[Patent Document 1]
JP-A-10-153194
[0007]
As shown in FIG. 9, a plurality of blades 125 of the cooling fan described in Patent Literature 1 have a predetermined shape of the main plate on one surface side of the main plate 121 in order to discharge air to the radial outside of the main plate 122 of the fan body 121. It extends from the radial position to the outer edge of the main plate, is arranged at a predetermined pitch along the circumferential direction of the main plate, and is provided to protrude from one surface side in the axial direction of the output shaft.
[0008]
When the cooling fan 120 is rotated, energy is given to the air by the centrifugal action, and the air passes through the air passage formed by the main plate 122, the blade 125, and the fan guide 131 from the inlet, which is the inner end of the blade 125. The air is discharged radially outward from an outlet, which is the outer periphery of the blade 125.
[0009]
Here, cooling fan 120 is provided with an inclination in the direction opposite to the rotation direction with respect to the direction in which the blades extend radially outward from a predetermined radial position on the main plate. This is because the noise generated during fan rotation generally contributes to the flow velocity, and the fluid noise is said to be proportional to the sixth power of the flow velocity. This is to reduce noise by lowering the peripheral speed. The protruding length of the blade 125 from the main plate 122 is set so that the flow velocity becomes equal or gradually decreases from the apex 125a on the inner diameter side of the blade 125 to the outer periphery when the fan rotates. More specifically, noise is reduced by making the product of the area, which is the product of the distance between the blades 125 in the circumferential direction of the main plate and the protruding length of the blades 125, and the diameter substantially equal at each radial position. That is, as shown in FIG. 9, L × h × D is constant when the interval between the blades and the protruding length of each blade at an arbitrary diameter D of the blades of the cooling fan are L and h, respectively. Thus, the cooling air flows smoothly, and the effect of noise reduction is exhibited.
[0010]
Here, as shown in FIG. 9, when the main plate 122 is provided at right angles to the rotation axis C, the main plate 122 warps due to the centrifugal force acting on the main plate 122 and the blades 125, and the main plate 122 is deformed and bent. There is a problem of doing. In particular, this problem becomes significant when the rotation speed of the motor is increased for the purpose of speeding up the grinding operation.
[0011]
In order to solve this problem, as shown in FIG. 10, the main plate 222 on which the blades are installed is not provided perpendicular to the rotation axis C, and the outer peripheral edge 222B of the main plate 222 is shifted from the base 222C of the main plate. Also, a configuration is implemented in which the main plate 222 is inclined so as to be positioned on the opposite side of the blade. With this configuration, the total center of gravity of the blade 125 and the main plate 222 can be brought closer to the blade root position, and warpage and deformation of the main plate 222 due to centrifugal force during rotation of the fan can be suppressed.
[0012]
However, when a force in the direction of the arrow X acts on the main plate 222 due to the rotation of the centrifugal fan, a tensile force acts on a connection portion between the hub 223 fitted to the output shaft and the base portion 222C of the main plate, and the main plate 222 may be damaged. There is. Therefore, as shown in FIG. 11, the hub 323 fitted to the output shaft extends in the axial direction of the output shaft not only in the blade side direction but also in the counter blade side direction. A configuration is provided in which a plurality of reinforcing ribs 326 extending in the radial direction of the main plate 222 at right angles to the axis C from the hub 323 to a portion having a surface 222D orthogonal to the axis C of the main plate are integrally provided.
[0013]
[Problems to be solved by the invention]
However, since the plurality of reinforcing ribs 326 extending in the radial direction are provided, the reinforcing ribs 326 similarly to the blades 125 generate an air flow by centrifugal action. The reinforcing ribs 326 have no configuration for reducing the noise related to the blades described above, and are likely to be faster than the flow velocity passing between the blades 125. Therefore, the flow velocity generated by the reinforcing ribs 326 becomes a factor of increasing noise. In particular, if the air discharge port of the power tool is positioned not on the blade side but on the reinforcing rib side, the sound source immediately communicates to the outside, and the problem of noise becomes apparent.
[0014]
In the configuration of FIG. 8, when a centrifugal fan having the same configuration as that of FIG. 11 is employed, the reinforcing rib 326 periodically passes through a projecting object, that is, a plurality of screws 115 protruding toward the fan. At this time, noise is generated due to fluctuations in air pressure. If two reinforcing ribs pass through the two screws 125 at the same time, the noise is doubled.
[0015]
Therefore, the present invention provides a power tool that suppresses noise generation while securing the strength of the hub and the main plate by optimizing the shape of the reinforcing rib and setting the flow rate generated by the reinforcing rib to be lower than the flow rate generated by the blade. It is an object of the present invention to provide a cooling fan for electric vehicles and a power tool provided with the cooling fan.
[0016]
[Means for Solving the Problems]
In order to achieve such an object, the present invention provides a disk-shaped main plate, and a cylindrical hub provided integrally and coaxially on a radially inner end side of the main plate to form a base of the main plate, A fan body fixed to an output shaft of the motor by a hub, and extending from a first predetermined radial position of the main plate to an outer edge of the main plate on one surface side of the main plate to discharge air radially outward of the main plate. A plurality of blades arranged along the circumferential direction of the main plate and protruding from the one surface side in the axial direction of the output shaft, the main plate having an outer edge in a direction opposite to the base portion than the base portion. The hub is provided to be inclined with respect to the axis of the output shaft so as to be located, the hub extends in the axial direction of the output shaft in the blade side direction and the anti-blade side direction, and the hub is provided on the other surface side of the main plate. And a plurality of reinforcing ribs extending in the radial direction of the main plate from the main plate to a second predetermined radial position of the main plate. In the electric tool cooling fan to be kicked,
An outer edge of the reinforcing rib other than a side integrated with the other surface of the main plate and the hub provides a cooling fan for a power tool having a shape approaching the blade side.
[0017]
Here, the protruding length of the blade from the one surface increases from a radially inner end of the blade to a third predetermined radial position, forms a peak at a third predetermined radial position, and starts from the third predetermined radial position. The second predetermined radial position, which has a shape that gradually decreases toward the radially outer end of the blade and forms the radially outer end of the plurality of reinforcing ribs, is located between the third predetermined radial position and the radial direction of the blade. Located between the ends.
[0018]
The present invention further provides a disk-shaped main plate, and a cylindrical hub integrally and coaxially provided on a radially inner end side of the main plate and serving as a base of the main plate, and the hub forms an output shaft of the motor by the hub. A fan body fixed to the main plate, extending from a first predetermined radial position of the main plate to an outer edge of the main plate on one surface side of the main plate to discharge air to a radial outside of the main plate, and extending in a circumferential direction of the main plate. A plurality of blades arranged along the one surface and protruding from the one surface side in the axial direction of the output shaft, wherein the main plate is provided with the output shaft such that the outer edge is located in a direction opposite to the blade with respect to the base. The hub extends in the blade direction and the anti-blade direction in the axial direction of the output shaft, and the other side of the main plate has a second predetermined radius of the main plate from the hub. A plurality of reinforcing ribs extending in the radial direction of the main plate to a position; The outer edges of the reinforcing ribs other than the other surface side of the main plate and the side integrated with the hub have a shape approaching the blade side, and are located at radially outer end positions of the plurality of reinforcing ribs. The second predetermined radial position is such that the flow rate of the radially outward air generated by the plurality of reinforcing ribs due to the rotation of the fan body is equal to or less than the radially outward air flow rate generated by the plurality of blades. The present invention provides a cooling fan for an electric tool set to be as follows.
[0019]
The present invention further provides an outer frame having an air inlet and an air outlet formed therein, a motor supported by the outer frame and having an output shaft, and disposed in the outer frame and connected to the output shaft. A cooling fan, wherein the cooling fan is provided with a disc-shaped main plate, and a cylindrical hub provided integrally and coaxially on the radially inner end side of the main plate to form a base of the main plate, A fan body fixed to the output shaft of the motor by the hub, and extending from a first predetermined radial position of the main plate to an outer edge of the main plate on one surface side of the main plate for discharging air radially outward of the main plate; A plurality of blades arranged along the circumferential direction of the main plate and protruding from the one surface side in the axial direction of the output shaft, the main plate having an outer edge in a direction opposite to the base portion than the base portion. The hub is provided so as to be inclined with respect to the axis of the output shaft, and the hub is A plurality of reinforcing ribs extending in the axial direction of the output shaft in the direction opposite to the blade side, and extending in the radial direction of the main plate from the hub to a second predetermined radial position of the main plate on the other surface side of the main plate. In the power tool, wherein the air discharge port is located on the other surface side with respect to the main plate, an outer edge of the reinforcing rib other than a side integrated with the other surface side of the main plate and the hub is An electric tool having a shape approaching the blade side is provided.
[0020]
The present invention further provides an outer frame having an air inlet and an air outlet formed therein, a motor supported by the outer frame and having an output shaft, and disposed in the outer frame and connected to the output shaft. A cooling fan, wherein the cooling fan is provided with a disc-shaped main plate, and a cylindrical hub provided integrally and coaxially on the radially inner end side of the main plate to form a base of the main plate, A fan body fixed to the output shaft of the motor by the hub, and extending from a first predetermined radial position of the main plate to an outer edge of the main plate on one surface side of the main plate for discharging air radially outward of the main plate; A plurality of blades arranged along the circumferential direction of the main plate and protruding from the one surface side in the axial direction of the output shaft, the main plate having an outer edge in a direction opposite to the base portion than the base portion. The hub is provided so as to be inclined with respect to the axis of the output shaft, and the hub is A plurality of reinforcing ribs extending in the axial direction of the output shaft in the direction opposite to the blade side, and extending in the radial direction of the main plate from the hub to a second predetermined radial position of the main plate on the other surface side of the main plate. In the power tool, wherein the air discharge port is located on the other surface side with respect to the main plate, an outer edge of the reinforcing rib other than a side integrated with the other surface side of the main plate and the hub is The second predetermined radial position, which has a shape approaching the blade side and is a radially outer end position of the plurality of reinforcing ribs, is directed radially outward where the plurality of reinforcing ribs are generated by rotation of the fan body. An electric power tool is provided in which the flow velocity of air is set to be equal to or lower than the flow velocity of air flowing outward in the radial direction in which the plurality of blades are generated.
[0021]
In the electric power tool described above, the length of the blade protruding from the one surface increases from a radially inner end of the blade to a third predetermined radius position and peaks at a third predetermined radius position, and the third predetermined radius A position gradually decreasing from a position toward a radially outer end of the blade, wherein the second predetermined radial position formed by the radially outer ends of the plurality of reinforcing ribs is the third predetermined radial position and the radius of the blade. It is located between the inner ends in the direction.
[0022]
In the power tool described above, the outer frame has a casing having the air suction port formed at one end thereof, and a gear cover formed with the discharge port connected to the other end of the casing. The gear cover is disposed at a position directly facing the other surface of the main plate, and the power tool functions as a grinding tool by rotatably supporting a rotating grindstone by the gear cover, and a plurality of screws are provided at a constant circumferential interval. It is fixed to the other end of the casing and protrudes toward the other surface of the main plate and is arranged directly facing the plurality of reinforcing ribs,
The plurality of reinforcing ribs are arranged at regular intervals in the circumferential direction. When the number of the reinforcing ribs is odd, the even number of the screws are provided, and when the number of the reinforcing ribs is even, the number of the screws is odd.
[0023]
Alternatively, in the above-described power tool, in order to prevent free rotation of the output shaft, the outer frame body may traverse the diametrical direction of the main plate at a position directly opposed to the other surface of the main plate and extend in the diametrical direction. An elongated spindle lock that is movable and selectively engages with the output shaft is provided, and a circular saw is detachably provided on a side of the spindle lock opposite to the cooling fan, so that the power tool can be cut by the cutting tool. , And an odd number of the plurality of reinforcing ribs are provided at regular circumferential intervals.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
A power tool according to a first embodiment of the present invention will be described with reference to FIGS. The first embodiment relates to a cutting tool.
[0025]
The cutting tool 1 has an outer frame formed by a main body housing 2 and a gear cover 3, an air inlet 2 a is formed at one end of the main body housing 2, and a motor 5 having an output shaft 4 is supported inside the main body housing 2. Is done. An air passage a1 communicating with the air suction port 2a is defined between the rear of the motor 5 and the main body housing 2, and an air passage a1 is provided between the outer periphery of the motor 5 and the inner peripheral surface of the main body housing 2. An air passage a2 extending in the axial direction of the motor is defined. A cooling fan 20 is provided coaxially on the output shaft 4. Further, between the motor 5 and the cooling fan 20, an air passage a3 communicating with the air passage a2 and extending outward in the radial direction of the cooling fan 20 is defined.
[0026]
The gear cover 3 has one end fixed to the other end of the main body housing 2 with screws 6, and a circular saw case 7 integrally provided at the other end. In the gear cover 3, the output shaft 4 is rotatably supported via a bearing 11, and the drive shaft 9 is rotatably supported via a bearing 12. A pinion gear 7 is fixed to the output shaft 4, and a gear 10 that meshes with the pinion gear 7 is coaxially fixed to the drive shaft 9. The pinion gear 7 and the gear 10 constitute a power transmission mechanism and are disposed in the gear cover 3. A discharge port 3a communicating with an air passage a3 in the main body housing 2 is formed in the gear cover 3, and an air passage a4 is defined in the discharge port 3a. A circular saw blade 13 is detachably fixed to the drive shaft 9, and a safety cover 14 is rotatably supported by the drive shaft 9. The space between the circular saw blade 13 and the circular saw case 7 communicates with the air passage a4 to define an air passage a5 communicating with the outside.
[0027]
As shown in FIG. 2, a gap is partially formed at the boundary between the main body housing 2 and the gear cover 3, and a spindle lock 15 for preventing free rotation of the output shaft 4 is provided in the gap. I have. The spindle lock 15 is provided to prevent the free rotation of the drive shaft 9 when the cutting tool 1 is not operated and to facilitate replacement of the circular saw blade 13.
[0028]
The spindle lock 15 is a long plate-shaped member that is provided across the diameter direction of the cooling fan 20 and is movable in the diameter direction as indicated by an arrow A in FIG. One end of the spindle lock 15 projects to the outside of the outer frame and can be operated from outside. As shown in FIG. 3, the output shaft 4 includes a deformed cross section 4A having surfaces parallel to each other, and a forked portion 15A that engages with the deformed cross section 4A to prevent the output shaft 4 from rotating; It has a rotation permitting portion 15B which communicates with the portion 15A and is disengaged from the deformed section 4A, and other arms 15X and 15Y extending in directions opposite to each other. Therefore, when the spindle lock 15 is operated to move in the direction of arrow A, the forked portion 15A engages with the deformed cross-section 4A to prevent free rotation of the output shaft 4, thereby preventing free rotation of the drive shaft 9, and When the moving operation is performed in the direction of the arrow A, the rotation permitting portion 15B is positioned around the deformed section 4A, and the rotation of the output shaft 4 is permitted.
[0029]
As shown in FIG. 2, the cooling fan 20 is an integrally molded product including a fan main body 21, a plurality of blades 25, and a plurality of reinforcing ribs 26. With respect to the fan body 21, the blade 25 is provided on the side facing the motor 5, and the reinforcing rib 26 is provided on the side facing the spindle lock 15. The above-described discharge port 3a is located at a position deviated toward the reinforcing rib 26 side.
[0030]
As shown in FIGS. 4 to 6, the fan main body 21 includes a disc-shaped main plate 22 and a cylindrical hub integrally and coaxially provided on a radially inner end side of the main plate 22 and forming a base of the main plate 22. The cooling fan 20 is fixed to the output shaft 4 by press-fitting the hub 23 into the output shaft 4 of the motor 5. The plurality of blades 25 extend from the first predetermined radial position 22A of the main plate 22 to the outer edge 22B of the main plate 22 on one surface side (the side facing the motor 5) of the main plate 22, and are arranged at a predetermined pitch along the circumferential direction of the main plate 22. Is done. And it is provided so as to protrude in the direction of the motor 5 from one side. Here, the main plate 22 is provided so as to be inclined with respect to the axis C of the output shaft 4 so that the outer edge 22B is located in the direction opposite to the blade 25 from the base 22C, and the hub 23 is in the direction toward the blade and in the direction opposite to the blade. The output shaft 4 extends in the axial direction.
[0031]
In order to reduce noise by lowering the flow velocity of air passing between the blades 25 during rotation of the cooling fan 20 from the rotation peripheral speed of the cooling fan 20 itself, as shown in FIG. Is inclined in a direction opposite to the rotation direction B with respect to a direction extending radially outward from the first predetermined radial position 22A of the main plate 22. The protruding length of the blade 25 from the main plate 22 is designed so that the flow velocity becomes equal or gradually decreases from the apex 25a on the inner diameter side of the blade 25 to the outer peripheral edge 22B when the fan rotates.
[0032]
In terms of shape, the protruding length of the blade 25 from one surface of the main plate 22 increases rapidly from the radial inner end 22A of the blade to a predetermined radial position (third predetermined radial position) 22D, and the third predetermined radius increases. A peak 25a is formed at the radial position, and the protruding length gradually decreases from the third predetermined radial position 22D toward the radial outer edge 22B of the blade. With such a configuration, the product of the radius, which is the product of the distance L between the blades 25 in the circumferential direction of the main plate and the protruding length of the blades, is substantially equal at each radial position, and thus noise can be reduced.
[0033]
The plurality of reinforcing ribs 26 are integrated with the main plate 22 on the other surface side (the side facing the spindle lock 15) of the main plate 22 from the hub 23 to a predetermined radial position (second predetermined radial position) 22E of the main plate 22. An odd number is provided at regular intervals extending in the radial direction and circumferentially. Here, the reinforcing rib 26 has a shape in which a protruding end (outer edge in the claims) is linear and approaches the blade 25 side as it goes radially outward.
[0034]
The radial outer ends (corresponding to the position of 22E) of the plurality of reinforcing ribs 26 are located between a third predetermined radial position 22D corresponding to the peak 25a of the blade 25 and the radial inner end 22A of the blade 25. This is because, in the centrifugal fan 20, the flow velocity between the blades 25 becomes the highest near the third predetermined radial position 22D, and the radial outer end diameter (22E) of the reinforcing rib 23 in order to maintain the strength of the main plate 22. This is because the diameter is required to be equal to or larger than the radial inner end diameter of the blade.
[0035]
In the above configuration, when the motor 5 rotates, the circular saw blade 13 rotates via the output shaft 4, the pinion gear 8, the gear 10, and the drive shaft 9, and a cutting operation can be performed. By the rotation of the motor 5, air is introduced into the main body housing 2 from the air suction port 2a, and air is introduced into the inner end side of the blade 25 of the cooling fan 20 through the air passages a1 and a2. Is forcibly introduced to the outer end side of the blade and discharged from the discharge port 3a to the outside air through the air passages a4 and a5. When the air passes through the passage a2 on the outer peripheral side of the motor 5 and the passage a5 on the outer peripheral edge of the circular saw blade 13, the motor 5 as a heating element is cooled.
[0036]
Since the discharge port 3a is biased toward the reinforcing rib 26, which is a sound source, the layout is such that noise can be easily transmitted outward. However, as described above, the outer edge of the reinforcing rib 26 extends radially outward. Since it has a shape approaching the blade 25 side, it is possible to secure the mechanical strength of the hub 23 and the main plate 22 which is the original function of the reinforcing rib, and at the same time, to reduce the radial length of the reinforcing rib 26. Therefore, the speed of the airflow generated by the reinforcing ribs 26 can be reduced, and the generation of noise due to the rotation of the reinforcing ribs 26 can be suppressed.
[0037]
Further, as described above, the radially outer ends (corresponding to the position of 22E) of the plurality of reinforcing ribs 26 are located at the third predetermined radial position 22D corresponding to the peak 25a of the blade 25 and the radially inner end 22A of the blade 25. , The flow velocity of the air flow generated by the reinforcing ribs 26 is lower than the flow velocity of the air flow generated by the blades 25, and sufficient strength can be obtained without increasing noise. .
[0038]
Further, each rotation of the centrifugal fan 20 causes each reinforcing rib 26 to pass through the spindle lock 15 twice. That is, it passes through the arm 15X and the arm 15Y of the spindle lock. Even when the reinforcing rib 26 passes through the spindle lock 15, it is inevitable that noise is generated due to a sudden pressure change of air. Although this noise is small as a noise value, the noise is unpleasant due to the generation of high frequency and gives discomfort. In the present embodiment, the plurality of reinforcing ribs 26 are arranged at equal intervals in the circumferential direction of the main plate 22 but are odd, so that the two reinforcing ribs 26 do not pass over the spindle lock 15 at the same time. Can be Therefore, simultaneous generation of noise can be prevented.
[0039]
FIG. 7 shows a modification of the cooling fan, and the same parts as those in FIG. 5 are denoted by the same reference numerals and description thereof will be omitted. In the cooling fan 30 shown in FIG. 7, the shape of the protruding end of the reinforcing rib 36 is not linear, but has a bulging arc shape. Even with such an arc shape, the above-described reinforcing effect of the main plate 22 and the hub 23 and the noise reduction effect can be exhibited.
[0040]
In the grinding tool shown in FIG. 8, the noise reduction effect can be achieved by employing the cooling fans shown in FIGS. 5 to 7 instead of the cooling fan 120. When the cooling fan shown in FIGS. 5 to 7 is adopted in the configuration of FIG. 8, each reinforcing rib passes through two screws 115 protruding in the direction of the cooling fan, and at that time, the pressure fluctuation of air causes Noise will be generated. Thus, as in the above-described embodiment, the number of reinforcing ribs is set to an odd number so that the two reinforcing ribs do not pass through the two bolts 115 at the same time, thereby preventing simultaneous generation of noise.
[0041]
The power tool according to the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made within the scope described in the claims. For example, when a large number of protrusions (for example, the screw 115 in FIG. 8) protruding in the direction of the reinforcing rib, which is a source of noise, are provided at regular intervals in the circumferential direction, if the number is odd, the reinforcing rib is replaced. The number may be even, and if the number of protrusions is even, the number of reinforcing ribs may be odd. The outer edge of the reinforcing rib may be not only a continuous straight line as shown in FIG. 5 or an arc shape as shown in FIG. 7, but also a discontinuous line having a corner. In the latter case, the edge may be constituted by a first edge rising vertically from the hub with respect to the axis C, and a second edge perpendicular to the blade side from the first edge. In addition, it is needless to say that the cooling fan according to the above-described embodiment can be adopted for electric tools other than the above-described cutting tool and grinding tool.
[0042]
【The invention's effect】
According to the cooling fan for an electric tool according to the first aspect, since the outer edge of the reinforcing rib other than the other surface of the main plate and the side integrated with the hub is shaped closer to the blade side, the reinforcing rib has an original shape. The mechanical strength of the hub and the main plate, which is a function, can be secured, and at the same time, the length of the reinforcing ribs in the radial direction can be reduced. Generation of noise due to rotation of the ribs can be suppressed.
[0043]
According to the cooling fan for the power tool of the second aspect and the power tool of the sixth aspect, the radially outer end of each reinforcing rib is located between the third predetermined radial position and the radially inner end of the blade. With this configuration, the flow velocity of the air flow generated by the reinforcing ribs is lower than the flow velocity of the air flow generated by the blades, and sufficient strength can be obtained without increasing noise.
[0044]
According to the cooling fan for an electric tool of the third aspect, the outer edge of the reinforcing rib other than the other surface of the main plate and the side integrated with the hub has a shape approaching the blade side, and the radial direction of the plurality of reinforcing ribs. The second predetermined radial position, which is the outer end position, is determined by the radially outward air flow rate at which the plurality of reinforcing ribs are generated by the rotation of the fan body and the radially outward air flow rate at which the plurality of blades are generated. Since the setting is made as follows, it is possible to suppress the generation of noise due to the rotation of the reinforcing rib.
[0045]
According to the power tool of the fourth aspect, the discharge port is biased toward the reinforcing rib which is a sound source, and the layout is such that noise is easily transmitted outward. Since the outer edge other than the other side of the main plate and the side integrated with the hub is shaped closer to the blade side, the radial length of the reinforcing rib can be reduced, and the air flow generated by the reinforcing rib can be reduced. Can be reduced, and generation of noise due to rotation of the reinforcing ribs can be suppressed.
[0046]
According to the electric power tool of the fifth aspect, the discharge port is biased toward the reinforcing rib, which is a sound source, similarly to the fourth aspect, and the layout is such that noise can be easily transmitted to the outside. The outer edge of the reinforcing rib other than the other side of the main plate and the side integrated with the hub has a shape approaching the blade side, and a second predetermined radial position which is a radial outer end position of the plurality of reinforcing ribs. Is set so that the flow velocity of the radially outward air in which a plurality of reinforcing ribs are generated by the rotation of the fan body is equal to or less than the flow velocity of the radially outward air in which the plurality of blades are generated. In addition, the generation of noise due to the rotation of the reinforcing rib can be suppressed.
[0047]
According to the power tool of claim 7, when the power tool is a grinding tool, an even number of protrusions are provided when the number of the reinforcing ribs is odd, and the screws are provided when the number of the reinforcing ribs is even. Since an odd number is provided, it is possible to prevent a situation where two reinforcing ribs pass over two screws at the same time, and it is possible to prevent a noise from being duplicated.
[0048]
According to the power tool of the eighth aspect, when the power tool is a cutting tool, since an odd number of reinforcing ribs are provided, it is possible to prevent a situation in which two reinforcing ribs pass through the spindle lock at the same time, thereby reducing noise. Can be prevented from occurring.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment in which a power tool according to the present invention is applied to a cutting tool.
FIG. 2 is a partial cross-sectional plan view of the cutting tool of FIG. 1 according to an embodiment of the present invention.
FIG. 3 is a view of the cutting tool of FIG. 1 according to the embodiment of the present invention, with a main body housing removed, as viewed from the direction of arrow III of FIG. 2;
FIG. 4 is a partial front view showing a cooling fan according to the embodiment of the present invention.
FIG. 5 is a partial cross-sectional view of the cooling fan according to the embodiment of the present invention.
FIG. 6 is a rear view of the cooling fan according to the embodiment of the present invention.
FIG. 7 is a partial sectional view showing a modification of the cooling fan shown in FIGS. 4 to 6;
FIG. 8 is a sectional view showing a grinding tool as an example of a conventional electric tool.
FIG. 9 is an explanatory view showing a conventional cooling fan.
FIG. 10 is a partial sectional view showing a conventional cooling fan in which a fan main body is inclined with respect to a rotation axis.
FIG. 11 is a partial cross-sectional view showing a configuration in which reinforcing ribs are provided in the cooling fan of FIG.
[Explanation of symbols]
1: cutting tool, 2: body housing, 3: gear cover, 4: output shaft, 5: motor, 15: spindle lock, 20: cooling fan, 21: fan body, 22: main plate, 22A: first predetermined radial position 22B: outer edge, 22C: base, 22D: third predetermined radial position, 22E: second predetermined radial position, 23: hub, 25: blade, 25a: inner side apex, 26 36: reinforcing rib

Claims (8)

円板状の主板と、該主板の半径方向内端側に一体且つ同軸に設けられて該主板の基部をなす筒状のハブとが設けられ、該ハブによりモータの出力軸に固定されるファン本体と、
空気を該主板の半径方向外方に排出するために、該主板の一面側において該主板の第１所定半径位置から該主板の外縁まで延び、該主板の周方向に沿って配列され、該一面側から該出力軸の軸方向に突出して設けられた複数の羽根を備え、
該主板は、該外縁が該基部よりも反羽根側方向に位置するように該出力軸の軸心に対して傾斜して設けられ、該ハブは羽根側方向と反羽根側方向に該出力軸の軸方向に延び、
該主板の他面側には該ハブから該主板の第２所定半径位置まで該主板の半径方向に延びる複数の補強リブが一体に設けられる電動工具用冷却ファンにおいて、
該補強リブの、該主板の他面側及び該ハブと一体化する辺以外の外縁は、該羽根側に近づく形状をなすことを特徴とする電動工具用冷却ファン。A fan provided with a disk-shaped main plate and a cylindrical hub integrally and coaxially provided on the radially inner end side of the main plate and forming a base of the main plate, and fixed to the output shaft of the motor by the hub Body and
In order to discharge air outward in the radial direction of the main plate, the main plate extends from a first predetermined radial position of the main plate to an outer edge of the main plate on one surface side of the main plate, and is arranged along a circumferential direction of the main plate. A plurality of blades provided so as to protrude from the side in the axial direction of the output shaft,
The main plate is provided so as to be inclined with respect to the axis of the output shaft so that the outer edge is located in a direction opposite to the base with respect to the blade, and the hub is provided with the output shaft in the direction toward the blade and in the direction opposite to the blade. Extends in the axial direction of
A power tool cooling fan, wherein a plurality of reinforcing ribs extending in a radial direction of the main plate from the hub to a second predetermined radial position of the main plate are integrally provided on the other surface side of the main plate,
A cooling fan for an electric tool, wherein an outer edge of the reinforcing rib other than the other surface side of the main plate and a side integrated with the hub has a shape approaching the blade side. 該羽根は該一面からの突出長が、該羽根の半径方向内端から第３所定半径位置までは増加して第３所定半径位置でピークをなし、該第３所定半径位置から該羽根の半径方向外端に向かって徐々に減少する形状をなし、該複数の補強リブの半径方向外端をなす該第２所定半径位置は、該第３所定半径位置と該羽根の半径方向内端との間に位置することを特徴とする請求項１記載の電動工具用冷却ファン。The protruding length of the blade from the one side increases from a radially inner end of the blade to a third predetermined radius position and peaks at a third predetermined radius position, and a radius of the blade from the third predetermined radius position The plurality of reinforcing ribs has a radially outer end, and the second predetermined radial position is a position between the third predetermined radial position and the radial inner end of the blade. The cooling fan for an electric tool according to claim 1, wherein the cooling fan is located between the cooling fans. 円板状の主板と、該主板の半径方向内端側に一体且つ同軸に設けられて該主板の基部をなす筒状のハブとが設けられ、該ハブによりモータの出力軸に固定されるファン本体と、
空気を該主板の半径方向外方に排出するために該主板の一面側において該主板の第１所定半径位置から該主板の外縁まで延び、該主板の周方向に沿って配列され、該一面側から該出力軸の軸方向に突出して設けられた複数の羽根を備え、
該主板は、該外縁が該基部よりも反羽根側方向に位置するように該出力軸の軸に対して傾斜して設けられ、該ハブは羽根側方向と反羽根側方向に該出力軸の軸方向に延び、
該主板の他面側には該ハブから該主板の第２所定半径位置まで該主板の半径方向に延びる複数の補強リブが一体に設けられる電動工具用冷却ファンにおいて、
該補強リブの、該主板の他面側及び該ハブと一体化する辺以外の外縁は、該羽根側に近づく形状をなし、
該複数の補強リブの半径方向外端位置となる該第２所定半径位置は、該ファン本体の回転により該複数の補強リブが発生する半径方向外方に向かう空気の流速が、該複数の羽根が発生する半径方向外方に向かう空気の流速以下となるように設定されることを特徴とする電動工具用冷却ファン。A fan provided with a disk-shaped main plate and a cylindrical hub integrally and coaxially provided on the radially inner end side of the main plate and forming a base of the main plate, and fixed to the output shaft of the motor by the hub Body and
In order to discharge air outward in the radial direction of the main plate, the main plate extends from a first predetermined radial position of the main plate to an outer edge of the main plate on one surface side of the main plate, and is arranged along a circumferential direction of the main plate. A plurality of blades provided to protrude in the axial direction of the output shaft from
The main plate is provided so as to be inclined with respect to the axis of the output shaft so that the outer edge is located in a direction opposite to the base with respect to the blade, and the hub is provided with the output shaft in the direction toward the blade and in the direction opposite to the blade. Extend in the axial direction,
A power tool cooling fan, wherein a plurality of reinforcing ribs extending in a radial direction of the main plate from the hub to a second predetermined radial position of the main plate are integrally provided on the other surface side of the main plate,
An outer edge of the reinforcing rib other than the other surface side of the main plate and a side integrated with the hub has a shape approaching the blade side,
The second predetermined radial position, which is a radially outer end position of the plurality of reinforcing ribs, is such that the flow rate of radially outward air generated by the plurality of reinforcing ribs due to rotation of the fan body is reduced by the plurality of blades. The cooling fan for an electric tool is set to be equal to or less than a flow rate of air flowing outward in a radial direction in which the airflow occurs. 空気吸入口と空気吐出口が形成された外枠体と、
該外枠体内に支持され出力軸を備えるモータと、
該外枠体内に配置されると共に該出力軸に接続される冷却ファンとを備え、該冷却ファンは、
円板状の主板と、該主板の半径方向内端側に一体且つ同軸に設けられて該主板の基部をなす筒状のハブとが設けられ、該ハブによりモータの出力軸に固定されるファン本体と、
空気を該主板の半径方向外方に排出するために該主板の一面側において該主板の第１所定半径位置から該主板の外縁まで延び、該主板の周方向に沿って配列され、該一面側から該出力軸の軸方向に突出して設けられた複数の羽根を備え、
該主板は、該外縁が該基部よりも反羽根側方向に位置するように該出力軸の軸心に対して傾斜して設けられ、該ハブは羽根側方向と反羽根側方向に該出力軸の軸方向に延び、
該主板の他面側には該ハブから該主板の第２所定半径位置まで該主板の半径方向に延びる複数の補強リブが一体に設けられ、
該空気吐出口は、該主板に関して該他面側に偏して位置する電動工具において、
該補強リブの、該主板の他面側及び該ハブと一体化する辺以外の外縁は、該羽根側に近づく形状をなすことを特徴とする電動工具。An outer frame body formed with an air inlet and an air outlet,
A motor supported in the outer frame and having an output shaft;
A cooling fan arranged in the outer frame and connected to the output shaft, wherein the cooling fan
A fan provided with a disk-shaped main plate and a cylindrical hub integrally and coaxially provided on the radially inner end side of the main plate and forming a base of the main plate, and fixed to the output shaft of the motor by the hub Body and
In order to discharge air outward in the radial direction of the main plate, the main plate extends from a first predetermined radial position of the main plate to an outer edge of the main plate on one surface side of the main plate, and is arranged along a circumferential direction of the main plate. A plurality of blades provided to protrude in the axial direction of the output shaft from
The main plate is provided so as to be inclined with respect to the axis of the output shaft so that the outer edge is located in a direction opposite to the base with respect to the blade, and the hub is provided with the output shaft in the direction toward the blade and in the direction opposite to the blade. Extends in the axial direction of
A plurality of reinforcing ribs extending in the radial direction of the main plate from the hub to a second predetermined radial position of the main plate are integrally provided on the other surface side of the main plate,
In the power tool, the air discharge port is biased toward the other surface with respect to the main plate,
An electric tool, wherein an outer edge of the reinforcing rib other than the other surface side of the main plate and a side integrated with the hub has a shape approaching the blade side. 空気吸入口と空気吐出口が形成された外枠体と、
該外枠体内に支持され出力軸を備えるモータと、
該外枠体内に配置されると共に該出力軸に接続される冷却ファンとを備え、該冷却ファンは、
円板状の主板と、該主板の半径方向内端側に一体且つ同軸に設けられて該主板の基部をなす筒状のハブとが設けられ、該ハブによりモータの出力軸に固定されるファン本体と、
空気を該主板の半径方向外方に排出するために該主板の一面側において該主板の第１所定半径位置から該主板の外縁まで延び、該主板の周方向に沿って配列され、該一面側から該出力軸の軸方向に突出して設けられた複数の羽根を備え、
該主板は、該外縁が該基部よりも反羽根側方向に位置するように該出力軸の軸心に対して傾斜して設けられ、該ハブは羽根側方向と反羽根側方向に該出力軸の軸方向に延び、
該主板の他面側には該ハブから該主板の第２所定半径位置まで該主板の半径方向に延びる複数の補強リブが一体に設けられ、
該空気吐出口は、該主板に関して該他面側に偏して位置する電動工具において、
該補強リブの、該主板の他面側及び該ハブと一体化する辺以外の外縁は、該羽根側に近づく形状をなし、
該複数の補強リブの半径方向外端位置となる該第２所定半径位置は、該ファン本体の回転により該複数の補強リブが発生する半径方向外方に向かう空気の流速が、該複数の羽根が発生する半径方向外方に向かう空気の流速以下となるように設定されることを特徴とする電動工具。An outer frame body formed with an air inlet and an air outlet,
A motor supported in the outer frame and having an output shaft;
A cooling fan arranged in the outer frame and connected to the output shaft, wherein the cooling fan
A fan provided with a disk-shaped main plate and a cylindrical hub integrally and coaxially provided on the radially inner end side of the main plate and forming a base of the main plate, and fixed to the output shaft of the motor by the hub Body and
In order to discharge air outward in the radial direction of the main plate, the main plate extends from a first predetermined radial position of the main plate to an outer edge of the main plate on one surface side of the main plate, and is arranged along a circumferential direction of the main plate. A plurality of blades provided to protrude in the axial direction of the output shaft from
The main plate is provided so as to be inclined with respect to the axis of the output shaft so that the outer edge is located in a direction opposite to the base with respect to the blade, and the hub is provided with the output shaft in the direction toward the blade and in the direction opposite to the blade. Extends in the axial direction of
A plurality of reinforcing ribs extending in the radial direction of the main plate from the hub to a second predetermined radial position of the main plate are integrally provided on the other surface side of the main plate,
In the power tool, the air discharge port is biased toward the other surface with respect to the main plate,
An outer edge of the reinforcing rib other than the other surface side of the main plate and a side integrated with the hub has a shape approaching the blade side,
The second predetermined radial position, which is a radially outer end position of the plurality of reinforcing ribs, is such that the flow rate of radially outward air generated by the plurality of reinforcing ribs due to rotation of the fan body is reduced by the plurality of blades. The power tool is set so as to be equal to or lower than the flow velocity of air flowing outward in the radial direction in which the airflow occurs. 該羽根は該一面からの突出長が、該羽根の半径方向内端から第３所定半径位置までは増加して第３所定半径位置でピークをなし、該第３所定半径位置から該羽根の半径方向外端に向かって徐々に減少する形状をなし、該複数の補強リブの半径方向外端なす該第２所定半径位置は、該第３所定半径位置と該羽根の半径方向内端との間に位置することを特徴とする請求項４乃至５記載の電動工具。The protruding length of the blade from the one side increases from a radially inner end of the blade to a third predetermined radius position and peaks at a third predetermined radius position, and a radius of the blade from the third predetermined radius position A radially outer end of the plurality of reinforcing ribs is located between the third predetermined radial position and the radially inner end of the blade. The power tool according to claim 4, wherein 該外枠体は、一端部側に該空気吸入口が形成されたケーシングと、該ケーシングの他端部に接続され該吐出口が形成されたギヤカバーとを有し、該ギヤカバーは該主板の他面に直接対向する位置に配置され、該ギヤカバーにより回転砥石を回転可能に支承して該電動工具は研削工具として機能し、
複数のネジが一定の周方向間隔で該ケーシングの他端部に固定されると共に該主板の他面に向かって突出して該複数の補強リブに直接対向して配列され、
該複数の補強リブは一定の周方向間隔で配列され、該補強リブが奇数個のときは該ネジは偶数個設けられ、該補強リブが偶数個のときは該ネジが奇数個設けられることを特徴とする請求項４乃至５記載の電動工具。The outer frame has a casing having the air suction port formed at one end and a gear cover connected to the other end of the casing and having the discharge port formed therein. The power tool functions as a grinding tool, being arranged at a position directly facing the surface, rotatably supporting a rotating grindstone by the gear cover,
A plurality of screws are fixed to the other end of the casing at a constant circumferential interval and are arranged directly protruding toward the other surface of the main plate so as to directly face the plurality of reinforcing ribs,
The plurality of reinforcing ribs are arranged at regular intervals in the circumferential direction. When the number of the reinforcing ribs is odd, the number of the screws is provided. When the number of the reinforcing ribs is even, the number of the screws is provided. The power tool according to claim 4 or 5, wherein 該出力軸の自由回転を阻止するために、該外枠体には、該主板の他面に直接対向する位置に該主板の直径方向に横切りかつ該直径方向に移動可能で該出力軸と選択的に嵌合する長尺状のスピンドルロックが設けられ、該スピンドルロックに関し該冷却ファンと反対側には丸鋸が着脱可能に設けられて該電動工具を切断工具として機能させ、該複数の補強リブは一定の周方向間隔で奇数個設けられることを特徴とする請求項４乃至５記載の電動工具。In order to prevent free rotation of the output shaft, the outer frame body is traversed in the diameter direction of the main plate and is movable in the diameter direction at a position directly facing the other surface of the main plate so that the outer frame body can be selected from the output shaft. An elongated spindle lock is provided which is fitted to the cooling fan, and a circular saw is detachably provided on the side opposite to the cooling fan with respect to the spindle lock, so that the power tool functions as a cutting tool, and the plurality of reinforcements are provided. 6. The power tool according to claim 4, wherein an odd number of ribs are provided at a constant circumferential interval.
JP2003015799A 2003-01-24 2003-01-24 Cooling fan for electric tool, and electric tool equipped with cooling fan Pending JP2004225642A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010000571A (en) * 2008-06-20 2010-01-07 Makita Corp Electrical power tool
JP2012080603A (en) * 2010-09-30 2012-04-19 Hitachi Koki Co Ltd Disk motor and electric power tool
JP2014079873A (en) * 2012-09-26 2014-05-08 Makita Corp Power tool
JP2017082802A (en) * 2017-02-20 2017-05-18 日本電産株式会社 Centrifugal fan
JP2017144552A (en) * 2012-09-26 2017-08-24 株式会社マキタ Electric power tool
WO2018061556A1 (en) * 2016-09-30 2018-04-05 日立工機株式会社 Electric power tool
US10662969B2 (en) 2012-03-12 2020-05-26 Nidec Corporation Centrifugal fan

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010000571A (en) * 2008-06-20 2010-01-07 Makita Corp Electrical power tool
JP2012080603A (en) * 2010-09-30 2012-04-19 Hitachi Koki Co Ltd Disk motor and electric power tool
US10662969B2 (en) 2012-03-12 2020-05-26 Nidec Corporation Centrifugal fan
JP2014079873A (en) * 2012-09-26 2014-05-08 Makita Corp Power tool
JP2017144552A (en) * 2012-09-26 2017-08-24 株式会社マキタ Electric power tool
WO2018061556A1 (en) * 2016-09-30 2018-04-05 日立工機株式会社 Electric power tool
JPWO2018061556A1 (en) * 2016-09-30 2018-12-27 工機ホールディングス株式会社 Electric tool
DE212017000224U1 (en) 2016-09-30 2019-05-06 Koki Holdings Co., Ltd. Electrically powered tool
JP2017082802A (en) * 2017-02-20 2017-05-18 日本電産株式会社 Centrifugal fan

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